84 research outputs found
Effects of a feeding strategy to increase intramuscular fat content of pork under the conditions of organic farming
In an ongoing study, the effect of the implementation of a specific feeding strategy using a high portion of home-grown grain legumes on the intramuscular fat (IMF) content of pork, is assessed under different conditions on organic farms in Germany and Austria. Preliminary results indicate that variation in the IMF content seems to be higher between farms than between treatments within each farm
Untersuchung zukunftsorientierter FĂŒtterungskonzepte fĂŒr laktierende Zuchtsauen in der Biologischen Landwirtschaft
Im vorliegenden Projekt wurden mittels partizipativen Ansatzes Lösungsmöglichkeiten fĂŒr die Problematik der â100% BiofĂŒtterungâ von laktierenden Zuchtsauen entwickelt. Dazu wurden 2 Rationen im Exaktversuch ĂŒber 2 Jahre getestet: eine Ration wies einen niedrigen Proteingehalt und eine unausgewogene AminosĂ€urenzusammensetzung auf. Die zweite Ration wurde diesbezĂŒglich weitgehend optimiert. Etwa zu Mitte des Exaktversuchs wurden die gewonnenen Erkenntnisse auf 4 Praxisbetrieben umgesetzt. Aus den nach diesen Untersuchungen vorliegenden Daten lassen sich fĂŒr Beratung und Praxis folgende Erkenntnisse ableiten: Sauen können Minderversorgungen durch Rationen, die unter den empfohlenen Gehalten fĂŒr die Protein- und insbesondere die AminosĂ€urenausstattung liegen, weitgehend kompensieren. Dies setzt allerdings eine hohe Futteraufnahme voraus. Eine negative Beeinflussung der Fruchtbarkeit der Sauen und der Ferkelverluste in der SĂ€ugezeit durch eine Unterversorgung mit essentiellen AminosĂ€uren wĂ€hrend der Laktation ist unter VerhĂ€ltnissen, wie sie in den vorliegenden Versuchen bestanden, nicht zu erwarten. Die tendenzielle Verschlechterung der Fruchtbarkeit in der unbalancierten Gruppe des Exaktversuchs lĂ€sst aber doch vermuten, dass hier die Untergrenze fĂŒr eine gerade noch akzeptable Versorgungssituation erreicht wurde. FĂŒr Beratung und Praxis lĂ€sst sich daraus die Empfehlung ableiten, dass Betriebe, die ihre laktierenden Sauen in Hinkunft (nach Auslaufen der Ăbergangsfrist laut EG-Verordnung Ende 2011) bewusst mit diesen knapp formulierten Rationen fĂŒttern wollen, unbedingt ein professionelles FĂŒtterungsmanagement sicherstellen mĂŒssen. Dazu gehören insbesondere regelmĂ€Ăige Futtermittelanalysen, da die Schwankungen des NĂ€hrstoffgehalts in den Futtermitteln relativ groĂ sein können, wie auch in der vorliegenden Untersuchung dokumentiert wurde. Die bei niedriger bzw. unbalancierter AminosĂ€urenversorgung der Sauen nicht auszuschlieĂende verminderte Lebendmasse-Entwicklung der Ferkel ist aus der Sicht der Praxis von groĂer Bedeutung. Dies ist deshalb besonders relevant, da die Formulierung geeigneter Saugferkel-Beifutter und Ferkelaufzuchtfutter unter den Bedingungen einer 100 % Bio-FĂŒtterung von den Betriebsleitern als besondere Herausforderung angesehen wird
Evaluating the potential of dietary crude protein manipulation in reducing ammonia emissions from cattle and pig manure: A meta-analysis
Dietary manipulation of animal diets by reducing crude protein (CP) intake is a strategic NH3 abatement option as it reduces the overall nitrogen input at the very beginning of the manure management chain. This study presents a comprehensive meta-analysis of scientific literature on NH3 reductions following a reduction of CP in cattle and pig diets. Results indicate higher mean NH3 reductions of 17 ± 6% per %-point CP reduction for cattle as compared to 11 ± 6% for pigs. Variability in NH3 emission reduction estimates reported for different manure management stages and pig categories did not indicate a significant influence. Statistically significant relationships exist between CP reduction, NH3 emissions and total ammoniacal nitrogen content in manure for both pigs and cattle, with cattle revealing higher NH3 reductions and a clearer trend in relationships. This is attributed to the greater attention given to feed optimization in pigs relative to cattle and also due to the specific physiology of ruminants to efficiently recycle nitrogen in situations of low protein intake. The higher NH3 reductions in cattle highlights the opportunity to extend concepts of feed optimization from pigs and poultry to cattle production systems to further reduce NH3 emissions from livestock manure. The results presented help to accurately quantify the effects of NH3 abatement following reduced CP levels in animal diets distinguishing between animal types and other physiological factors. This is useful in the development of emission factors associated with reduced CP as an NH3 abatement option
Quantitative modeling of superconducting planar resonators with improved field homogeneity for electron spin resonance
We present three designs for planar superconducting microwave resonators for
electron spin resonance (ESR) experiments. We implement finite element
simulations to calculate the resonance frequency and quality factors as well as
the three-dimensional microwave magnetic field distribution of the resonators.
One particular resonator design offers an increased homogeneity of the
microwave magnetic field while the other two show a better confinement of the
mode volume. We extend our model simulations to calculate the collective
coupling rate between a spin ensemble and a microwave resonator in the presence
of an inhomogeneous magnetic resonator field. Continuous-wave ESR experiments
of phosphorus donors in Si demonstrate the feasibility of our
resonators for magnetic resonance experiments. We extract the collective
coupling rate and find a good agreement with our simulation results,
corroborating our model approach. Finally, we discuss specific application
cases for the different resonator designs
Tunable magnon-magnon coupling in synthetic antiferromagnets
In this work, we study magnon-magnon coupling in synthetic antiferromagnets
(SyAFs) using microwave spectroscopy at room temperature. Two distinct
spin-wave modes are clearly observed and are hybridised at degeneracy points.
We provide a phenomenological model that captures the coupling phenomena and
experimentally demonstrate that the coupling strength is controlled by the
out-of-plane tilt angle as well as the interlayer exchange field. We
numerically show that a spin-current mediated damping in SyAFs plays a role in
influencing the coupling strength.Comment: 13 pages, 11 figures(including supplementary
Maser threshold characterization by resonator Q-factor tuning
Whereas the laser is nowadays an ubiquitous technology, applications for its microwave
analog, the maser, remain highly specialized, despite the excellent low-noise microwave
amplification properties. The widespread application of masers is typically limited by the need
of cryogenic temperatures. The recent realization of a continuous-wave room-temperature
maser, using NVâ centers in diamond, is a first step towards establishing the maser as a
potential platform for microwave research and development, yet its design is far from optimal. Here, we design and construct an optimized setup able to characterize the operating
space of a maser using NVâ centers. We focus on the interplay of two key parameters for
emission of microwave photons: the quality factor of the microwave resonator and the degree
of spin level-inversion. We characterize the performance of the maser as a function of these
two parameters, identifying the parameter space of operation and highlighting the requirements for maximal continuous microwave emission
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